1. Field of the Invention
The present invention relates to a method of manufacturing semiconductor devices having a capacitor above a semiconductor substrate, such as of a hollow cylindrical capacitor structure.
2. Description of the Background Art
In manufacturing a semiconductor device having a capacitor above a semiconductor substrate, such as DRAMs having a memory cell of a hollow cylindrical capacitor structure, it has been necessary to form a storage node direct contact for electrical connection between a storage node electrode disposed above the capacitor and the semiconductor device components disposed on the semiconductor substrate.
FIGS. 9 to 11 are cross sections illustrating steps in a conventional method of manufacturing a DRAM having a memory cell of a hollow cylindrical capacitor structure. Specifically, FIGS. 9 and 10 show intermediate stages of manufacture, and FIG. 11 shows the final product.
Referring to FIG. 9, an interlayer BP (Boron, Phosphorus)-TEOS layer 22, interlayer BP-TEOS layer 23, SS (Storage node Stopper) nitride film 24 and interlayer BP-TEOS layer 25 are disposed on a semiconductor substrate 21. Bit line 29 is selectively disposed on the interlayer BP-TEOS layer 22. The structure so constructed is subjected to photolithography and etching process, to form a hole extending through the interlayer BP-TEOS layer 25, SS nitride layer 24, interlayer BP-TEOS layer 23 and interlayer BP-TEOS layer 22, thereby to provide a plug 30 composed of polysilicon in the hole.
Referring to FIG. 10, an interlayer BP-TEOS layer 26 is formed on the interlayer BP-TEOS layer 25 including the plug 30, an upper TEOS layer 27 is formed on the interlayer BP-TEOS layer 26, and a patterned resist 31 is formed on the upper TEOS layer 27.
By using the resist 31 as a mask, an etching process of the upper TEOS layer 27 and interlayer BP-TEOS layer 26 is performed to form a hollow cylindrical groove for metallization (not shown). Then, as shown in FIG. 11, a storage node electrode 34, capacitor insulating film 36 and cell plate node electrode 37 are formed successively, thereby obtaining a capacitor 38 of a hollow cylindrical structure consisting of these components 34, 36 and 37. At this time, the plug 30 functions as a storage node direct contact (i.e., a direct contact between the storage node electrode 34 of the capacitor 38 and a component disposed on the surface of the semiconductor substrate 21).
The conventional method of manufacturing DRAMs of a hollow cylindrical capacitor structure is performed as described above, which necessitates the step of forming the plug 30 for storage node direct contact. This step therefore causes an increase in the number of steps and in the cost of manufacture.